Conventional sighting telescopes typically are fitted with one or more sighting accessories which are configured, depending on the design, in the first image plane near the objective and/or in the second image plane near the ocular of said telescope. Usually an optical reversal system is configured between the two image planes. On one hand, said reversal system is used to reverse the vertically and laterally inverted image. On the other hand, the reversal system is able to control the magnification of the telescope.
A number of different sighting accessories are known in the state of the art. One such accessory may be a reticle. Frequently a reticle is a crossed-lines grid made by etching or subtended by inserted wires, its structuring allowing a variety of patterns. A very popular design is the crosshairs. Besides such relatively plain geometries, more complex reticles also are known. Illustratively, their features may allow improving the distance-to-target determination. Illuminating means are frequently used to discern the reticle on the target image even under poor light conditions or at dusk
Another kind of sighting accessory is described in the German patent document DE 299 03 989 U1. This document discloses a sighting telescope comprising a beam splitter which is configured between a system ocular and objective lens and slants with respect to an optic axis, further a projection element to generate a target mark visible from the ocular, said projection element being fitted with a light source and the beam splitter together constituting one common unit displaceable as a whole. A dimmable and switchable light source may be also provided to match the target mark to the varying light conditions.
When the sighting accessory is situated in the sighting telescope's first image plane, that is in front of the reversal system, then, in the course of a change in magnification, said accessory is jointly magnified, respective reduced, with the target object. As a result the relation between sighting accessory and target object always remains constant regardless of the particular magnification. By means of the sighting accessory dimension relative to the target object it is possible to determine said object's distance. However, the drawback to this method is that at large magnifications, the sighting accessory masks a large portion of target object.
The sighting accessory is situated behind the reversal system when situated in the second image plane. A change in magnification entails only the size of the target object while the sighting accessory's dimensions always remain the same. Consequently this design of the sighting accessory cannot be used to determine the distance to the target.
German patent document DE 20 2008 012 601 U1 discloses a target optics with a first crosshairs image situated in a second image plane nearest the objective and a target dot reticle configured in a second image plane nearest the ocular. A switchable illumination element is provided for both reticles. Consequently, both reticles may be used jointly or independently of each other depending on the state of illumination.
By means of the above discussed disclosure, both the advantages of a reticle in the first image plane and that of a reticle in the second image plane are being used. However a significant drawback is incurred in that the target mark in the second image plane is fully visible even when the illuminating element has been shut off. As a result, the target image is at least partly masked. Masking the target image both distracts the marksman and lowers the reliability of hitting the target.
Based on this state of the art, it is the object of the present invention to create a sighting telescope offering substantial support to the marksman both for rapid fire, for instance in beater hunts, and for accurate long-range firing. Moreover the sighting telescope shall enable distance measurement.